We Keep Coding

javascript - avoid repetable code

I have a page with a button that calls a menu modal. The modal contains two more buttons that call two submenus - one for each button. Watch the pen:
https://codepen.io/t411tocreate/pen/yoxJGO
It actually works. But the current problem is that I re-write a repeatable code to call each submenu:
$('.show-submenu-1').on('click', function () {
$('.submenu-1.offcanvas').addClass('offcanvas--active');
})
$('.show-submenu-2').on('click', function () {
$('.submenu-2.offcanvas').addClass('offcanvas--active');
})
This approach seems to be pretty dumb. I need a solution with less repetition, something like forEach function for arrays:
var menus = [
'.show-submenu-1',
'.show-submenu-2'
];
menus.forEach(function(menu){
$(menu).on('click', function () {
$(`${menu}.offcanvas`).addClass('offcanvas--active');
})
});
Of course, this scenario won't work. How can I make my code DRY?

Use markup:
<div class="submenu" data-index="1">
<div class="submenu" data-index="2">
<button class="show-submenu-button" data-submenu-index="1">
<button class="show-submenu-button" data-submenu-index="2">
Then:
$('.show-submenu-button').on('click', function () {
var index = $(this).attr('data-submenu-index');
$('.submenu[data-index="' + index + '"]').addClass('offcanvas--active');
})
There is little value to using classnames that are so specific that they identify every element on the page individually. Classnames should define a class of elements that behave the same way.

Hi I hope I got the question right but you could use data-attributes for something like this. Just set a general class for .show-submenu and mark their connection to the menus with a number in a data-submenu=x attribute. Where x would be the number in .submenu-x.
And then you do something like this:
Notice that i changed .show-submenu-1 to .show-submenu. Make sure every trigger has this class. Also add a data-submenu=x for every submenu you want to use.
$('.show-submenu').on('click', function () {
var number = $(this).attr("data-submenu");
var selector = '.submenu-' + number + '.offcanvas'
$(selector).addClass('offcanvas--active');
})
So the data-submenu is used to pair the trigger and the modal. This way you can stick to an easy to read html code and a short bit of jquery.

Try this:
var menus = [1, 2];
menus.forEach(index => {
$(`.show-submenu-${index}`).on('click', () => {
$(`.submenu-${index}.offcanvas`).addClass('offcanvas--active');
});
});

You can use this as well.
$('.show-submenu-1, .show-submenu-2').on('click', function (event) {
$(event.target).hasClass('show-submenu-1'){
$('.submenu-1.offcanvas').addClass('offcanvas--active');
}else{
$('.submenu-2.offcanvas').addClass('offcanvas--active');
}
})
it would be better to have your show-submenu-1(as showmenu) and submenu-1(as submenu) in same parent element that allows you to use closest() method and make life easy
for eg:
$('.show-submenu').on('click', function (event) {
$(event.target).closest('.submenu').addClass('offcanvas--active');
})

How to reduce this jquery toggle code for an image map

I am trying to figure out how to reduce this code down! it basically hides an image then show a div depending on what image map area is clicked!
I have a code pen of a working demo here: http://codepen.io/naniio/pen/wBExYq
$(document).ready(function() {
$(".auckland").click(function() {
$(".map").toggle();
$("#aukl.hide").toggle();
});
$(".gisborne").click(function() {
$(".map").toggle();
$("#gisb.hide").toggle();
});
$(".wellington").click(function() {
$(".map").toggle();
$("#well.hide").toggle();
});
$(".nelson").click(function() {
$(".map").toggle();
$("#nel.hide").toggle();
});
$(".christchurch").click(function() {
$(".map").toggle();
$("#chch.hide").toggle();
});
$(".queenstown").click(function() {
$(".map").toggle();
$("#queen.hide").toggle();
});
$(".otago").click(function() {
$(".map").toggle();
$("#ota.hide").toggle();
});
});
I have tried using find and other jquery methods but I must be looking in the wrong places
Any help would be great I'm new to jQuery but not new to stack overflow I can imagine this is an easy question/fix for some and this may be rated harshly or ignored! but for those who continually help this community regardless, thanks! :)

I have something working in this pen. http://codepen.io/anon/pen/ByOEam
Just add an extra attribute in the area tags
$(document).ready(function() {
$(".clickable").click(function() {
var toHide = $(this).attr('data-hide');
$(".map").toggle();
$("#"+toHide).toggle();
});
$(".hide").click(function() {
$(".map").toggle();
$(this).toggle();
});
});

A little refactoring to <area> tags like this
<area shape="circle" coords="220,97,15" alt="Auckland" title="Auckland" href="#" data-ref="aukl.hide">
would cleanup your html from unnecessary classes and would give you cleaner javascript code:
$(document).ready(function() {
$("map area").click(function() {
$(".map").toggle();
$("#" + this.data("ref")).toggle();
});
});

Add class to the all the div that will be clicked, say "lands", and use following code,
$(".lands").click(function() {
var $this = $(this);
$(".map").toggle();
$this.toggle();
});

Try this reduced jquery code
$(document).ready(function() {
$('.box').on('click',function(){
$(".map").toggle();
$(this).toggle();
});
});

Every time you need to add the same behavior to many different objects probably a good pattern is to use a function and dynamic creation.
For example in your specific case I'd expect to have
An image with the map (without dots)
A list of locations (possibly retrieved from a DB)
Code that for each of the locations creates the dot image correctly positioned on the map
Something like:
function addLocation(x, y, name, data) {
var dot = document.createElement("img");
dot.className = "dot";
dot.onload = function() {
// x,y coordinates are relative to map size to account
// for responsive designs
dot.left = (x*mapContainer.offsetWidth - dot.offsetWidth/2) + "px";
dot.top = (y*mapContainer.offsetHeight - dot.offsetHeight/2) + "px";
mapContainer.appendChild(dot);
};
dot.src = "dot.png";
dot.onclick = function() {
showMap(name, data);
};
}
This way adding/changing a location only requires updating the database (or the static data array if using a database is not worth at the moment).
Adding by hand location names and chart names (that are random small variations one of the other like gisborne->gisb but christchurch->chch) is a step toward making the page a maintenance nightmare.

Can you do a loop to change array size depending on the number of photos in a file in javascript/php?

Sorry for the question isn't very clear, basically
I have got the php code to search for photos in the directory based on the userId given in the url. So if the userId = 1, it will go to Photos/1 and get all the photos in that directory and output it into an array that I can use in Javascript. It works.
I have an external javascript to my php/html code.
I am changing the attr of the div's to display the photos. I have 5 "photo containers" in the array called photodisplay:
var photodisplay =
[
$("#photo1"),
$("#photo2"),
$("#photo3"),
$("#photo4"),
$("#photo5"),
];
Then I have a loop to change the attribute/img src:
function preloadingPhotos() {
for (var x=0; x<galleryarray.length; x++)
{
photodisplay[x].attr("src", "Photos/" + userid + "/" + galleryarray[x]);
console.log("preloaded photos");
}
displayPhoto();
}
It works. Providing no more than 5 photos because that is how many photocontainers I have. But what if I had photos? The question is: Would I be able to do a loop to keep changing the photos in the photodisplay array?
I also have code for the photocontainers to fade in and out:
function displayPhoto(){
photodisplay[0].fadeIn(3000);
photodisplay[0].delay(3000).fadeOut(3000, function() { //first callback func
photodisplay[1].fadeIn(3000);
photodisplay[1].delay(3000).fadeOut(3000, function() { //second callback func
photodisplay[2].fadeIn(3000);
photodisplay[2].delay(3000).fadeOut(3000, function() { //third callback func
photodisplay[3].fadeIn(3000);
photodisplay[3].delay(3000).fadeOut(3000, function() { // fourth callback func
photodisplay[4].fadeIn(3000);
photodisplay[4].delay(3000).fadeOut(3000, function() {
setTimeout(displayPhoto(), 3000);
});
});
});
});
});
}// end of function displayPhoto
Which requires me to manually enter the number of the array of the photodisplay.
I would thinking of adding more to the array with duplications of the photocontainers. But I don't think that would work since I would have to manually enter the number of the array in the code above to make it fade in and out.
Sorry if this is confusing. I tried my best to explain my problem. I hope someone can help. Don't worry about the retrieving images in the directory part, because it works. It increases the array of photos accordingly, I just don't know how to adjust this change with my javascript.

The method you are using, does not scale as you have a callback function for every element in your slideshow.
What you should do, is put all images in a list (or a list of div's) and hide them all / change the z-index so that only the active one shows. The you can loop through your elements using .next() on the list items to get the next one (or the first one if .next().length is 0).
This will clean up your code and is pretty easy to do yourself but there are also loads of jQuery plugins that do it for you.

You need a little bit of abstraction here. So instead of manually code numbers, try another approach. For this example I've used jQuery; since you've tagged your question with it, I assume it's okay:
// Set a default value and store the current photo in it.
var currentPhoto = 0;
// Calculate the total number of photos
var photoTotal = photodisplay.length;
var photoTimeout = false;
// Create a function to go to the next photo
var nextPhoto = function () {
// Keep track of the new current
currentPhoto = (currentPhoto + 1) % photoTotal;
// Just to be sure clearTimeout
clearTimeout(photoTimeout);
// Fadein each photo; you might want to do something to reset the style
photodisplay[0].fadeIn({
duration: 3000,
complete: function () {
photoTimeout = setTimeout(nextPhoto, 3000);
}
});
}
nextPhoto();

You don't want to define JS from the backend like that; just have PHP render the markup, then use JS to query and parse the markup for the presentational layer.
Let's assume your markup looks like this:
<div id="photocontainers">
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
</div>
<!-- A hidden array of images. -->
<div id="images">
<img src="http://placehold.it/100x100&text=1" />
<img src="http://placehold.it/100x100&text=2" />
<img src="http://placehold.it/100x100&text=3" />
<img src="http://placehold.it/100x100&text=4" />
<img src="http://placehold.it/100x100&text=5" />
<img src="http://placehold.it/100x100&text=6" />
<img src="http://placehold.it/100x100&text=7" />
<img src="http://placehold.it/100x100&text=8" />
<img src="http://placehold.it/100x100&text=9" />
<img src="http://placehold.it/100x100&text=10" />
<img src="http://placehold.it/100x100&text=11" />
</div>
So your server renders this; #images is just a hidden container, that basically preloads all the image assets you'll cycle between in #photocontainers.
var cycleImages = function() {
// Cache selectors that we'll need.
var $photoContainers = $('#photocontainers').children(),
$images = $('#images img'),
// Use `.data()` to get the starting point, or set to 0
// (if this is the first time the function ran).
startImage = $images.data('nextImage') || 0;
// Loop from the starting point, filling up the number of
// photocontainers in the DOM.
for (var i = startImage; i < startImage + $photoContainers.length; i++) {
var $targetImage = $images.eq(i % $images.length),
$targetPhotoContainer = $photoContainers.eq(i - startImage);
// Get rid of the current contents.
$targetPhotoContainer.empty();
// Clone the desired image, and append it into place.
$targetImage.clone().appendTo($targetPhotoContainer).fadeOut(0).fadeIn();
}
// Let's figure out which starting image is next up, and store that
// with `.data()`.
var nextImage = startImage + $photoContainers.length;
if (nextImage >= $images.length) {
nextImage -= $images.length;
}
$images.data('nextImage', nextImage);
}
// When the DOM is ready, call the method, then
// call it again however often you'd like.
$(document).ready(function() {
cycleImages();
setInterval(function() {
cycleImages();
}, 3000);
});
Here's a plunkr showing that in action: http://plnkr.co/SumqkXYpRXcOqEhAPOHm

How do I show or hide div, based on position of another div

I have the following jquery that slides a div horizontally:
$('.nextcol').click(function() {
$('.innerslide').animate({'left': '-=711px'}, 1000);
});
$('.prevcol').click(function() {
$('.innerslide').animate({'left': '+=711px'}, 1000);
});
What I want to happen is this... if the div.innerslide has a position that is left: 0px then I want to hide div.backarrow. If the position is not left: 0px, then it shows it.
Any help would be greatly appreciated.
EDIT (added HTML Markup)
<div class="backarrow prevcol">
<div id="mainleft" class="overflowhidden">
<div class="innerslide">
<div class="col">my content including next</div>
<div class="col">my content including next</div>
<div class="col">my content including next</div>
</div>
</div>

Try this:
if ($('.innerslide').css("left") == 0) {
$('div.backarrow').hide();
} else {
$('div.backarrow').show();
}
Fix for Double-Click Issue:
From what you described in your comment about the issue when the visitor double-clicks, it sounds like the double-click is causing two of the animation events to fire. To keep this from happening, you can either disable the click handler while the animation is running and re-enable it once it is finished, or you can try to write a new thread to continually check the element's position. One of these solutions is not a good idea - I'll let you figure out which one :) - but the other actually has a very simple solution that requires little change to your existing code (and may actually reduce your overhead by a teeny weeny amount):
$('.nextcol').on("click.next", function() {
$('.innerslide').animate({'left': '-=711px'}, 1000, showHideBack());
$(this).off("click.next");
});
$('.prevcol').on("click.prev", function() {
$('.innerslide').animate({'left': '+=711px'}, 1000, showHideForward());
$(this).off("click.prev");
});
Then add this this line to showHideBack() (and a complementary one to showHideForward() if you are using that):
$('.nextcol').on("click.next".....
I suggest that you write a function to set each click handler and another to remove each one. This will make your live very easy and the whole solution should reduce overhead by removing unnecessary click handlers while the animation is running.
Note: the animation method often calls its callback before the animation finishes. As such, you may wish to use a delay before calling the showHide... method(s).
Let me know if you have any questions. Good luck! :)
UPDATE:
Here is the updated version of the fiddle you gave me with all bugs ironed out. It looks like I misunderstood part of your goal in my original solution, but I straightened it out here. I have also included the updated jQuery, here:
var speed = 1000;
var back = $("div.backarrow");
var next = $(".nextcol");
var prev = $(".prevcol");
var inner = $(".innerslide");
function clickNext(index) {
next.off("click.next");
inner.animate({
'left': '-=711px'
}, speed, function() {
back.show(); //this line will only be hit if there is a previous column to show
next.delay(speed).on("click.next", function() {
clickNext();
});
});
}
function clickPrev() {
prev.off("click.prev");
inner.animate({
'left': '+=711px'
}, speed, function() {
if (inner.css("left") == "0px") {
back.delay(speed).hide();
prev.delay(speed).on("click.prev", function() {
clickPrev();
});
} else {
back.delay(speed).show();
prev.delay(speed).on("click.prev", function() {
clickPrev();
});
}
});
}
next.on("click.next", function() {
clickNext();
});
prev.on("click.prev", function() {
clickPrev();
});​
I was going to also include a condition to check if you were viewing the last column, but, as I don't know what your final implementation will be, I didn't know if it would be applicable. As always, let me know if you need help or clarification on any of this. :)

You could try the step option — a callback function that is fired at each step of the animation:
$('.prevcol').click(function() {
$('.innerslide').animate({ left: '+=711px' },
{
duration: 1000,
step: function(now, fx) {
if (now === 0 ) {
$('div.backarrow').hide();
} else {
$('div.backarrow').show();
}
}
});
});
More examples of usage in this article The jQuery animate() step callback function

Basic jQuery slideUp/slideDown help

I was wondering if there was a function that I can add to this, that would show the data again, as in make it slide back down or something after a given set of time so you can go back and re-enter your data.
It currently just slides up after submit, and then shows the text.
$("#help").slideUp(function() {
$("#help").before('<div class="failMessage">SOME FAIL TEXT HERE</div>');
setTimeout(ShowControlsHideFailMessage,5000);
});
function ShowControlsHideFailMessage()
{
$("#help").slideDown();
$('.failMessage').addClass('hidden');
}

The code sample below will use the setTimeout function to call $("#help").slideDown() after 5 seconds. Also, If you want to hide the "FAIL TEXT", I'd suggest using a CSS class for that message like this:
$("#help").slideUp(function() {
$("#help").before('<div class="failMessage">SOME FAIL TEXT HERE</div>');
setTimeout(ShowControlsHideFailMessage, 5000);
});
function ShowControlsHideFailMessage()
{
$("#help").slideDown();
$('.failMessage').addClass('hidden');
}
You can use the class failMessage for red fonts or anything special to that message and then create a hidden class that sets the display to none.

Here's a better way:
var failMessage = $('<div class="failMessage" />');
failMessage.text('SOME FAIL TEXT HERE');
//Create the failMessage beforehand
$("#help")
.slideUp(function() {
$(this).before(failMessage);
})
.delay(5000)
.slideDown(function () {
failMessage.hide();
}​);​